Due to their small diameter and considerable length there is a risk of endoscope rod lenses shattering. During the handling of medical endoscopes in particular, it is unavoidable that they will be subjected to bending stress, so that shear forces are developed in the center. There is an especial risk to the cement layers used for fixing rod lenses together or fixing rod lenses to normal lenses.
According to the prior art the rod lenses always have a uniform diameter. However, as the ends are cemented to lenses having a larger diameter, an endangered cross-section is formed at this cementing point. If the rod lens arrangement is subject to bending stress within an endoscope, the cement layer may fracture.
The problem of the invention is to so improve the known rod lenses that the cementing points at the ends thereof have a better resistance to shattering than hitherto.